Sandy, My guess is the your AC unit doesn't have a heat strip in it. You will need to look at your model number and check and see if it came with it,Jim
Sandy,I know you are trying to sort out why the heating elements in your AC do not work but we found out in a previous camper a portable electric heater is capable of putting out the same amount of heat as the AC heating coils. The small portable heaters are typically much quieter and allow you to move the heat to where you need it most. These are relatively cheap and available from many sources including Walmart.